However, according to your own requirements, you can change system images and create your application for any android OS version you require.
The core parts of Android SDK including Tools, Android Platform Tools, latest Android platform, and latest Android system image for emulator are already included in the package.
With fully integrated software stack that enables seamless access to SDK tools, plugins and utilities, anyone can easily start producing your first Android applications. Android SDK for Mac is the official software development package for developers who want to create Android applications that can take full advantage from entire Android hardware and software ecosystem.